use the method in Revenue Procedure 200437 to allocate the payment to sources in and out of the United States. Revenue Procedure 2004-37, 2004-26 I.R.B.1099, is available at tvww.irs.qov/ irb/2004-26 IRBIar08.html. The earnings portion of a pension payment is U.S. source income if the trust is a U.S. t